1. Technical Field
The disclosure is related generally to turbo-machines. More specifically, the disclosure is related to closure buckets for turbo-machines.
2. Related Art
Conventional turbo-machines (e.g., gas turbine, steam turbine) are frequently utilized to generate power for electric generators. More specifically, a working fluid such as gas or steam is conventionally forced across sets of turbo-machine blades, which are coupled to the rotor of the turbo-machine. The force of the working fluid on the blades causes those blades (and the coupled body of the rotor) to rotate. In many cases, the rotor body is coupled to the drive shaft of a dynamoelectric machine such as an electric generator. In this sense, initiating rotation of the turbo-machine rotor can initiate rotation of the drive shaft in the electric generator, and cause that generator to generate an electrical current (associated with power output).
The rotor of the turbo-machine typically includes a plurality of stages of buckets (sometimes referred to as blades) positioned in series axially along the rotor. Each stage includes a circumferential arrangement of buckets positioned around the rotor. Each bucket is positioned circumferentially around the rotor by coupling a dovetail portion of the bucket base to a complementary rotor dovetail machined underneath the surface of the rotor. This machined rotor dovetail feature is axisymmetric and is typically segmented, such that the plurality of buckets are positioned within an opening of the complementary rotor dovetail and slidingly positioned within the complementary rotor dovetail until all buckets, except for a closure bucket, are in an operational position. The closure bucket is conventionally positioned to cover a gate opening (e.g., segmented portion) of the complementary rotor dovetail to maintain the remaining buckets in place on the rotor. However, due to the inherent coupling technique used for coupling the closure bucket to the rotor, the closure bucket and the complementary rotor dovetail, including the gate opening, may frequently experience over-stressing during operation of the turbo-machine. As a result of the operational stress, the rotor and components (e.g., buckets, closure bucket) coupled to the rotor may have a reduced operational life and/or may negatively affect the efficiency of the turbo-machine.